Abstract: An apparatus for controlling warp threads on weaving machines, particularly suited for control of warp threads on Jacquard type machines, for example selvedge machines. Control members are arranged to control movement of a warp thread and are adapted to be moved in arcuate paths by a reciprocatable member which reciprocates repeatedly. Selectively operable members cooperate with the control members to allow the control members to reciprocate fully with the reciprocatable members or to be held in a position in which the control members either reciprocate less than the reciprocatable members or do not reciprocate at all. The control members have abutting surfaces in different planes which slide relative to each other and which permit the control members to be positioned with the abutting surfaces facing each other with a combined thickness substantially the same as the overall thickness of one of the control members.